You might associate fluffy, white bunnies with a magician's stage show, but rabbits played a far more crucial role from the 1930s to the early 1960s -- as the key elements of pregnancy tests. While the method of injecting a rabbit with human urine to test for pregnancy has become little more than a curio of the past, the basic principles involved with testing urine date back thousands of years and continue to this day.

Physicians, healers and novices alike have studied human urine for insight into our biological processes for about 6,000 years [source: Armstrong]. Historians believe the physicians of ancient Egypt were the first to discover a method of detecting pregnancy through the study of urine.

Ancient Egypt's predominant pregnancy test involved, at one time, the woman consuming alcohol and dates until she vomited. If she grew nauseous very quickly, there was a good chance she was pregnant. The urine test soon replaced this method and became a far less distressful method -- the woman urinated on a pile of wheat and barley. If the increased estrogen levels in the urine caused the seeds to sprout, then it meant she was expecting. This marked the beginning of medical urine examination, but more importantly, laboratory medicine itself. More than 6,000 years of urine examination -- or uroscopy -- followed. Today, we know this medical discipline as urinalysis.

In the early 1930s, Dr. Maurice Friedman made a fascinating discovery at the University of Pennsylvania Medical School. He found that he could detect whether or not a woman was pregnant by injecting her urine into a female rabbit. Was this method the product of a diseased mind? Or was injecting a rabbit with what Victorian physicians called a "divine fluid" a logical advancement in medical science?

Hop to the next page to find out what makes rabbits the home pregnancy test of the animal world.

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